The objectives of this project are to identify and describe environmental and host determinants of cancer in areas at high risk of cancer through the use of analytical epidemiologic techniques, particularly case-control studies of specific cancers. Completed during the year were analyses of a) kidney cancer in Minnesota, where ethnic factors, cigarette smoking, and (among women) high relative weight were associated with renal adenocarcinoma, and cigarette smoking and long-term intake of certain analgesics were found to be risk factors for renal pelvis cancer; b) oral cancer among women in North Carolina, where, in addition to an increased risk associated with snuff use, risk was inversely related to diets high in fruits and vegetables; and c) lung cancer in Pennsylvania, where increased risks were found among long-term steel workers and with residence in proximity to a zinc smelter. Interviewing continued for case-control studies of respiratory cancer in New Jersey and coastal Texas; lung, stomach, and pancreas cancers in Louisiana; bladder cancer in rural New England; and esophageal cancer in coastal South Carolina. Pilot studies were completed in areas of China at high risk for lung and esophageal cancer and choriocarcinoma. In addition, plans were finalized for an intervention trial involving the distribution by barefoot doctors of vitamin-mineral supplements in an area of China with the world's highest rates of esophageal cancer. The pilot studies demontrated the feasibility of case-control and cohort investigations in China, indicating that participation rates are likely to be exceptionally high.